cache-manager-couchbase

Couchbase store for node cache manager
==================================

Couchbase cache store for node-cache-manager.

Installation
------------

``sh
npm install cache-manager-couchbase --save
`
or
`sh
yarn add cache-manager-couchbase
`

Usage Examples
--------------
See examples below on how to implement the Redis cache store.

$3

`js
var cacheManager = require('cache-manager');
var couchbaseStore = require('cache-manager-couchbase');

var config = {
connectionString: 'couchbase://127.0.0.1:8091',
connectionOptions: {
username: 'Administrator',
password: 'couchbase'
},
bucket: 'test-bucket',
ttl: 2
};

var couchbaseCache = cacheManager.caching({
connectionString: config.connectionString,
store: couchbaseStore,
connectionOptions: config.connectionOptions,
scope: config.scope,
bucket: config.bucket,
collection: config.collection,
ttl: 60
});

var ttl = 2;

couchbaseCache.set('foo', 'bar', { ttl: ttl }, (err) => {
if (err) {
throw err;
}

couchbaseCache.get('foo', (err, result) => {
console.log(result);
// >> 'bar'
couchbaseCache.del('foo', (err) => {
});
});
});

function getUser(id, cb) {
setTimeout(() => {
console.log("Returning user from slow database.");
cb(null, { id: id, name: 'Bob' });
}, 100);
}

var userId = 123;
var key = user_${userId};

// Note: ttl is optional in wrap()
couchbaseCache.wrap(key, (cb) => {
getUser(userId, cb);
}, { ttl: ttl }, (err, user) => {
console.log(user);

// Second time fetches user from redisCache
couchbaseCache
.wrap(key, () => getUser(userId))
.then(console.log)
.catch(err => {
// handle error
});
});
`

Couchbase Buckets
--------------

Couchbase use buckets, scopes and collection to segment customer. The cache-manager-couchbase configuration let you choose between all of them.

Example for couchbase pre-7.x (no scopes and collection):

`js
var config = {
connectionString: 'couchbase://127.0.0.1:8091',
connectionOptions: {
username: 'Administrator',
password: 'your-secret-p@ssw0rd'
},
bucket: 'your-bucket'
};
`

Example for couchbase >7.x:

`js
var config = {
connectionString: 'couchbase://127.0.0.1:8091',
connectionOptions: {
username: 'Administrator',
password: 'your-secret-p@ssw0rd'
},
bucket: 'your-bucket',
scope: 'your-scope',
collection: 'your-collection',
ttl: 2
};
`

Couchbase Connection
--------------

The configuration let you customise how the plugin connects to your couchbase cluster.

`js
var config = {
connectionString: 'couchbases://node1.example.com,node2.example.com',
connectionOptions: {
trustStorePath: '/path/to/ca/certificates.pem',
username: 'Administrator',
password: 'couchbase'
},
bucket: 'your-bucket'
};
`

connectionString let you provide one or multiple seed nodes and connectionOptions are passed right away to the underlying couchbase nodejs SDK so that you can use all options provided here on the couchbase documentation


Important! Setting up your bucket for cache-manager keys method
--------------

Once your couchbase bucket is set up you will need to create an index so that the keys method can effectively look up for your keys.

Here an example:

`sql
CREATE INDEX all_keys ON your-bucket((meta().id))
`


If you see an error like the following:

`
error properties: Object({ cause: Error: libcouchbase error 401, context: QueryErrorContext({ first_error_code: 4000, first_error_message: 'No index available on keyspace test-bucket that matches your query. Use CREATE INDEX or CREATE PRIMARY INDEX to create an index, or check that your expected index is online.', statement: 'SELECT RAW meta(b).id FROM test-bucket b WHERE REGEXP_CONTAINS(META(b).id, $PATTERN)', client_context_id: 'c1ed4896bea27e6c', parameters: '', http_response_code: 404, http_response_body: '' }) })
`
It means the above mentioned index is missing!


Keys method
--------------

The 'keys' method let you selectively extract keys. This selection on couchbase is implemented through a SQL query using the REGEXP_CONTAINS so tha you can use a regexp to select your keys.

Example:

`js
couchbaseCache.keys('f*')
`

Next Implementations
--------------

* auto provision keys` index
* Improve connection error handling
* Improve keys method performances
* Verify ttl method compliancy
* Upgrade Couchbase Cluster connection to a non-blocking mode (To Be Checked)